/*
** $Id: lmem.h $
** Interface to Memory Manager
** See Copyright Notice in lua.h
*/

#ifndef lmem_h
#define lmem_h

#include <stddef.h>

#include "llimits.h"
#include "lua.h"

#define luaM_error(L) luaD_throw(L, LUA_ERRMEM)

/*
** This macro tests whether it is safe to multiply 'n' by the size of
** type 't' without overflows. Because 'e' is always constant, it avoids
** the runtime division MAX_SIZET/(e).
** (The macro is somewhat complex to avoid warnings:  The 'sizeof'
** comparison avoids a runtime comparison when overflow cannot occur.
** The compiler should be able to optimize the real test by itself, but
** when it does it, it may give a warning about "comparison is always
** false due to limited range of data type"; the +1 tricks the compiler,
** avoiding this warning but also this optimization.)
*/
#define luaM_testsize(n, e) \
    (sizeof(n) >= sizeof(size_t) && cast_sizet((n)) + 1 > MAX_SIZET / (e))

#define luaM_checksize(L, n, e) \
    (luaM_testsize(n, e) ? luaM_toobig(L) : cast_void(0))

/*
** Computes the minimum between 'n' and 'MAX_SIZET/sizeof(t)', so that
** the result is not larger than 'n' and cannot overflow a 'size_t'
** when multiplied by the size of type 't'. (Assumes that 'n' is an
** 'int' or 'unsigned int' and that 'int' is not larger than 'size_t'.)
*/
#define luaM_limitN(n, t)                             \
    ((cast_sizet(n) <= MAX_SIZET / sizeof(t)) ? (n) : \
                                                cast_uint((MAX_SIZET / sizeof(t))))

/*
** Arrays of chars do not need any test
*/
#define luaM_reallocvchar(L, b, on, n) \
    cast_charp(luaM_saferealloc_(L, (b), (on) * sizeof(char), (n) * sizeof(char)))

#define luaM_freemem(L, b, s)   luaM_free_(L, (b), (s))
#define luaM_free(L, b)         luaM_free_(L, (b), sizeof(*(b)))
#define luaM_freearray(L, b, n) luaM_free_(L, (b), (n) * sizeof(*(b)))

#define luaM_new(L, t)          cast(t *, luaM_malloc_(L, sizeof(t), 0))
#define luaM_newvector(L, n, t) cast(t *, luaM_malloc_(L, (n) * sizeof(t), 0))
#define luaM_newvectorchecked(L, n, t) \
    (luaM_checksize(L, n, sizeof(t)), luaM_newvector(L, n, t))

#define luaM_newobject(L, tag, s) luaM_malloc_(L, (s), tag)

#define luaM_growvector(L, v, nelems, size, t, limit, e)             \
    ((v) = cast(t *, luaM_growaux_(L, v, nelems, &(size), sizeof(t), \
                                   luaM_limitN(limit, t), e)))

#define luaM_reallocvector(L, v, oldn, n, t)                     \
    (cast(t *, luaM_realloc_(L, v, cast_sizet(oldn) * sizeof(t), \
                             cast_sizet(n) * sizeof(t))))

#define luaM_shrinkvector(L, v, size, fs, t) \
    ((v) = cast(t *, luaM_shrinkvector_(L, v, &(size), fs, sizeof(t))))

LUAI_FUNC l_noret luaM_toobig(lua_State *L);

/* not to be called directly */
LUAI_FUNC void *luaM_realloc_(lua_State *L, void *block, size_t oldsize,
                              size_t size);
LUAI_FUNC void *luaM_saferealloc_(lua_State *L, void *block, size_t oldsize,
                                  size_t size);
LUAI_FUNC void luaM_free_(lua_State *L, void *block, size_t osize);
LUAI_FUNC void *luaM_growaux_(lua_State *L, void *block, int nelems,
                              int *size, int size_elem, int limit,
                              const char *what);
LUAI_FUNC void *luaM_shrinkvector_(lua_State *L, void *block, int *nelem,
                                   int final_n, int size_elem);
LUAI_FUNC void *luaM_malloc_(lua_State *L, size_t size, int tag);

#endif
